(1) Extension or addition to any existing authorised building, either horizontally or vertically or both shall be permitted, if the proposed extension/ addition satisfies the provisions in these rules, irrespective of whether the existing building conforms to the provisions in these rules or not:Provided that for the purpose of calculating maximum coverage and floor area ratio permissible, for calculating the total off street parking requirements and for determining minimum width of access to a building and plot as well as the width of the street giving access to the plot from the main street and fire fighting requirements, both the proposed extensions/additions and the existing building shall be taken into account.
(2) Separate and independent building shall be permitted in a plot already having one or more authorised buildings, if the proposed building satisfies the provisions of these rules, irrespective of whether the existing buildings in that plot satisfies the provisions of these rules or not: Provided that for the purpose of calculating maximum coverage and floor area ratio permissible, for calculating the total off street parking requirements and for determining minimum width of access to a building and plot as well as the width of the street giving access to the plot from the main street and fire fighting requirements both the proposed and the existing buildings in the plot shall be taken into account: Provided further that the distance between the proposed building and other existing buildings shall be governed by rule 27.
(3) Conversion of roof with the same or a different material or additional sheet roof for protection from sun and rain shall be permitted to any building, if not otherwise prohibited by these rules or main rules or the Act, irrespective of whether such building conforms to the provision in these rules or not: Provided that the clear distance of the roof edges from the plot boundaries shall not be reduced from the existing distance, but however where sufficient distance is available it can be reduced to such extent that the provisions regarding projections permissible into open space as provided in rule 27 shall be observed. Provided further that no portion of the roof shall encroach or project into the street or the neighbouring plots and water from the roof shall not be allowed to fall into the street or the neighbouring plots or the plot boundaries: Provided also that no permission shall be necessary for conversion of roof with grass, leaf or thatch: Note: When additional sheet roof protection is provided above existing terrace, if sufficient height is available between the terrace and sheet roof so as to make it usable space, provisions of sub rule (1) of rule 28 shall be applicable for non-residential buildings.
(4) Conversion of shutters or doors with the same or a different material or erection of shutters or doors shall be permitted in any building if not otherwise prohibited by these rules, irrespective of 'whether such building conforms to the provisions in these rules or not: Provided that the area or height of the building shall not be increased.